Adelaide2.5 Other groundwater assets

Supporting information

The volume reported (88,017 ML) represents the groundwater asset in the Adelaide region at 30 June 2013. The volume reported is comprised of the managed groundwater volume and the balance of recharged water credits,

In the Adelaide region the managed groundwater volume is the sum of the groundwater extraction limits (or allocation limits) and the non-licensed groundwater extractions described by the relevant water allocation plan. Recharged water credits accrue from water drained or discharged into a well within the prescribed groundwater resource. The recharged water credit balance is a portion of the recharge credit that may be carried forward (according to the rules detailed in the relevant water allocation plan).

The groundwater asset could not be separated into water table aquifers and underlying aquifers because allocation and extraction limits are not defined at those levels, but rather at the groundwater resource only.

The managed groundwater volume and recharged water credit balance, itemised by groundwater management area at 30 June 2012 and 30 June 2013, are provided in the following table.

Groundwater asset opening and closing volumes for the 2012–13 year

Groundwater management area

Managed groundwater volume1

Recharged water credit balance

Total groundwater asset

Allocation/ extraction limit (ML)

Non-licensed extraction volume (ML)

Volume at 30 June 2013 (ML)

Volume at 30 June 2012 (ML)

Volume at 30 June 2013 (ML)

Volume at 30 June 2012 (ML)

Barossa Prescribed Water Resources Area (PWRA)

7,147

0

0

0

7,147

7,147

McLaren Vale Prescribed Wells Area (PWA)

6,560

500

0

1

7,060

7,061

Northern Adelaide Plains PWA

–

–

1,661

4,501

1,661

4,501

Western Mount Lofty PWRA

70,325

1,824

0

0

72,149

72,149

Total

88,017

90,858

1 The managed groundwater volume is constant across years; therefore, the opening and closing balance for the managed groundwater volume does not change.

The volume reported for the groundwater asset did not include the following prescribed groundwater resources:

Northern Adelaide Plains PWA: although the Northern Adelaide Plains has an operational water allocation plan, the capacity of the resource is insufficient to meet the water use demands and as such the managed groundwater volume is not recognised as a groundwater asset.

Central Adelaide Plains PWA and Dry Creek PWA do not have operational water allocation plans and therefore a managed groundwater volume has not been determined for these resources.

Omission of these groundwater resources will have a material impact on the volume reported for the groundwater asset in the 2013 Account.

Resource assessments are in progress for the Adelaide Plains that will include Northern Adelaide Plains PWA, Central Adelaide Plains PWA and Dry Creek PWA. Further information on the status of the resource assessment can be found in the South Australian Department of Environment, Water and Natural Resources's Groundwater status reports.

For more information about the managed groundwater volume and recharged water credits, refer to the Water allocations section of the 'Contextual information'.

Provided by

South Australian Department of Environment Water and Natural Resources.

Method

Managed groundwater volume

Barossa PWRA

The sum of estimated underground water allocation volumes, detailed in the current Barossa PWRA Water Allocation Plan, is reported as the managed groundwater volume.

McLaren Vale PWA

The estimated sustainable yield and estimated stock and domestic extraction, detailed in the current McLaren Vale PWA Water Allocation Plan, is reported as the managed groundwater volume.

Western Mount Lofty Ranges PWRA

The sum of groundwater extraction limits and existing non-licensed extraction volumes, detailed in the Western Mount Lofty Ranges PWRA Water Allocation Plan.

Recharged water credit balance—all management areas in the Adelaide region

The opening and closing recharged water credit balance for the 2012–13 year was extracted from the WILMA licensing database.

Assumptions, limitations, caveats and approximations

Managed groundwater volume

The availability of information to complete a groundwater assessment, the method of assessing the groundwater resource, and the date of the groundwater assessment differs significantly between the management areas. The outcome of the groundwater assessment may produce an extraction limit or an allocation limit. These outcomes are treated in the same manner for the purposes of defining the groundwater asset.

Recharged water credit balance

The recharged water credit balance is reported as the groundwater asset rather than as the volume injected. The recharged water credit balance is influenced by the conditions for allocating recharge water stated in the relevant water allocation plan.